I would say a very safe bet would be Super Mario Galaxy. To me that is a game everyone can enjoy, from young children to adults. I remember playing it as a little kid (Mario Bros.) and that made me still a fan today. So regardless of the age of the person you are buying for, they should like it.

Games like Medal of Honor, Metroid Prime, may be for the older gamers. I view Mario Strikers Charged as a younger generation game since its not a sports game in the traditional sense (even though I'd play it).